The present invention relates generally to medical diagnostic equipment, and more particularly is a new construction for steerable diagnostic catheters.
Heart disease is one of the leading causes of death in the world. Heart disease is found in all countries and across all ages, socio-economic levels, occupations, and sexes. Because heart disease is so universally common, the diagnosis and treatment of heart disease is an immensely important field.
One of the chief difficulties in examining the heart is that, as with all internal organs, the defects cannot be readily seen. It is therefore necessary to use some instrument that enables the user to xe2x80x9cseexe2x80x9d inside the organ. One of the processes that enables physicians in the treatment of hear disease is an electrophysiological examination. This examination requires the use of a catheter with a plurality of ring electrodes on a distal end. In addition to the ring electrodes, the catheter may also carry one or more probes at its distal tip.
The catheter is introduced through the patient""s veins or arteries into the areas of the heart, or the associated blood vessels, which require analysis. Due to the many available probes and testing devices, it is not uncommon for the examining physician to have several catheters in use at a given time in a single patient""s heart. When this is the case, the catheter entry path becomes very congested. Due to the relatively large size of existing diagnostic catheters, it is sometimes necessary to remove one catheter and replace it with another during a procedure. In addition to the distinct possibility of dislodging the already positioned catheters, the removal of a catheter can itself damage the organ if the catheter is removed improperly or becomes entangled with another catheter.
Another of the shortcomings in the prior art catheter devices is that they are very difficult to position correctly in the vessel or organ being examined. There are only very limited means of guiding the catheter. Smaller existing art catheters are generally provided with a fixed curvature at the distal end.
Another problem inherent in the prior art devices is that the shape of the probes on the distal ends of the catheters is fixed. This contributes to the problem of congestion in the entry path, as a different catheter must be introduced when the physician wishes to examine different vessel and organ wall shapes and sizes. When a basket catheter is being used, a sheath must be placed over the multiple probes or basket to introduce the catheter into the vessel.
Accordingly, it is an object of the present invention to provide an electrophysiology catheter that comprises a means to steer the distal end while providing a main body that is more narrow than those of current art devices.
It is a further object of the present invention to provide a catheter which allows the size, shape, and direction of travel of a probe to be changed while in the vessel or organ. This innovation is particularly applicable to basket catheters.
The present invention is a diagnostic catheter with a steering means to direct the distal end of the catheter while it is inserted in a vessel. The device may include either a bi-directional steering mechanism, or a unidirectional steering mechanism. Pre-formed catheters with no steering means are also provided.
The catheter bodies include a plurality of ring electrodes used for sensing the intracardial electrogram signal during operation of the catheter. The ring electrodes are placed in ohmic contact with their corresponding signal wires by a solderless connection.
In addition, the catheter may be embodied as a basket catheter. The basket catheter includes a plurality of splines. After the catheter is inserted into the vessel or organ to be examined (typically the heart), the splines expand from an at-rest position to form the basket.
A central retractable and steerable member is included to provide the expansion force. The expansion force can be provided by moving the proximal portion of the catheter relative to the central member. Each of the splines forming the basket includes a spring wire therein to provide the compliance for the splines to be in contact with the organ while they are in the expanded position.
An advantage of the present invention is that although it is smaller in size than most current art devices, it can be steered in the vessel or organ being examined.
Another advantage of the present invention is that it has a large plurality of non-welded ring electrodes for sensing, even though the catheter is smaller in size than most current art devices.
A still further advantage of the present invention is that the distal end of the fixed shape of the catheter can be formed and fixed in any shape desired by the user.
Another advantage of the present invention is that when it is used as a basket catheter, the basket size and shape can be modified while the catheter is in use.
Yet another advantage of the present invention is that when the basket catheter version is in use, the basket can be steered in either expanded or collapsed state within the vessel or organ being examined.
Still another advantage of the present invention when it is used as a basket catheter is that no sheath is necessary for insertion of the catheter into the vessel or organ.
These and other objects and advantages of the present invention will become apparent to those skilled in the art in view of the description of the best presently known mode of carrying out the invention ad described herein and as illustrated in the drawings.